Protecting Concrete From Freezing

The protection period is the time required to prevent concrete from being affected by exposure to cold weather.

Protecting concrete from freezing.

Protect concrete from freeze thaw damage permanently protect concrete from freeze thaw damage by using creto deep penetrating sealer dps. At this point it is strong enough and dry enough to avoid damage by a single freezing cycle cyclic freeze thaw protection requires air entrained concrete and strength closer to 3500 psi. Special curing and protection is. Note that removing formwork when concrete is too cold or hasn t reached desired strength could damage concrete strength and surfaces and concrete might collapse.

Protect the concrete from freezing by external means i e blankets enclosures or heaters. Concrete absorbs moisture when. Concrete is one of the most durable building materials known to man but it can be vulnerable to deterioration from weather salts and the freeze thaw cycle. Protecting concrete in cold weather is a continuous challenge for concrete contractors and site supervisors.

This leads to increased salt damage to concrete driveways which is further amplified by the effect of the freeze thaw cycle. Using frost blankets and insulated formwork could be necessary to protect concrete. Modify the mix design so the concrete will gain the necessary strength before freezing or. When concrete is being placed below 5 degrees but is not below freezing point concrete will take longer to develop the required strength.

Placing concrete in the cold weather condition requires special preparation and protection. Protect the sub grade and the concrete from freezing i ve had concrete floors where the entire surface has peeled off top 1 8 because the general contractor refused to protect and insulate the concrete after we troweled it and the temperature dropped into the 20 s overnight. For more information see concrete basics on page 945 of this issue or the article cold weather finishing in the november 1993 issue of concrete construction. The exposure of concrete to cold weather will extend the time required for it to reach initial set which may require finishing crews to be available for a longer period.

See sidebar for more about this definition protect from early age freezing. Since the ground is a bit warmer and the concrete generates its own heat blankets will keep it warm even if the temperature goes below 20 f. Depending on the actual ambient temperature protection of a concrete placement may require the use of windbreaks enclosures or supplementary heat. Salt also lowers the freezing point of water and increases the pressure of frozen water thereby intensifying the effect of the freeze thaw cycle.

For flatwork the traditional and still the best way to protect concrete from the cold is to cover it with blankets after it s been finished.